The aim of this paper is to present a practical method to enable the planner to assess this new type of question. It does not require specialized data sets to define the model, nor the use of specialized software to implement.
As will be shown with the results of a study carried out for the city of Basel, Switzerland, the model can (and has been) successfully applied with a minimal set of input data consisting of a coded node/link network with calibrated volume delay functions, an outdated AM peak matrix and observed hourly volumes on a subset of links. The model was implemented by using only a standard version of the EMME/2 transportation planning software (see Spiess [
[Page]4]; INRO [2]) and a multiple linear regression program.The Basic State Model
The aim of our model is to provide means to estimate the traffic volumes 
for every link 
in the network and every hour of the day 
( 
)
.
Observed volumes 
are assumed to be available on a subset of links 
